The following description relates to one or more toric motors adapted to be incorporated into a lens barrel of a camera so as to drive a lens mechanism.
A toric motor has been used as a driving source for automatically driving a lens mechanism of a lens-replaceable camera. The toric motor generally has a stator and a rotor formed to be ring-shaped, respectively, which rotor is driven to be rotated in a circumferential direction. As examples of a motor of this type, an ultrasonic motor and a brushless motor have been proposed. For instance, a surface wave motor is employed as a motor of this type in Japanese Patent Provisional Publication No. HEI10-319298 (hereinafter referred to as '298 Publication). In the surface wave motor, a toric rotor is disposed around an outer circumferential surface of a toric stator, and rotatably supported by bearings around the stator. Further, a pressing member presses the rotor against the stator in an optical axis direction such that the rotor comes into a frictional contact with the rotor under a predetermined pressure. Thereby, due to a surface wave generated on the side of the stator, the rotor is rotated to drive a lens mechanism linked therewith.